Laterally diffused metal oxide semiconductor (LDMOS) transistors are mainly used in power integrated circuits. An LDMOS transistor is a semiconductor device that forms a lateral current path on the surface of a semiconductor substrate by planar diffusion. Thus, an LDMOS transistor often has many advantages such as thermal stability and frequency stability, relatively high gain, durability, relatively low feedback capacitance and thermal resistance, constant input impedance, and simple biasing current circuit.
For an LDMOS transistor used in a power integrated circuit, the on-resistance (Rdson) and breakdown voltage (BV) of the LDMOS transistor are two important indicators of the device performance. An LDMOS transistor is often desired to have a relatively high BV and a relatively low Rdson. However, the on-resistance (Rdson) and breakdown voltage (BV) of conventional LDMOS transistors cannot be simultaneously improved.
The disclosed semiconductor device and the method for forming the semiconductor device are directed to solve one or more problems set forth above and other problems.